lettuce

Lettuce is the Java client most Spring apps already use to talk to Redis: Spring Boot's Redis starter picks it by default. One thread-safe connection serves blocking, async and reactive calls, with Cluster, Sentinel, pub/sub, RediSearch and RedisJSON built in. MIT licensed, completely free.

Nothing to host. Add io.lettuce:lettuce-core from Maven Central and point it at Redis. It still runs on Java 8, and Redis Ltd. ships releases steadily (7.7 through 7.9 landed August to October 2026). Free for solo devs, small teams and large teams. Your only bill is the Redis server.

Lettuce for async, reactive or Spring work. Jedis, also from Redis, for a plainer client built for ease of use. Redisson for distributed locks, queues and Java collections on Redis, though its PRO edition is quote-only.

The catch: sharing a connection only works if threads avoid blocking and transaction commands like BLPOP and MULTI/EXEC. And 8.0 is in beta, dropping Reactor-based APIs that 7.8 and 7.9 deprecated, so reactive code has migration work coming. Redis's server license change doesn't touch this: Redis lists Lettuce as MIT, and the client moved from Apache 2.0 to MIT in 2024.